Preheat the oven to 425 degrees F (220 degrees C).

Mix beets, 1 tablespoon olive oil, 1/4 teaspoon salt, and 1/8 teaspoon black pepper together on a baking sheet.

Roast in the preheated oven until beets are tender, about 40 minutes.

Mix roasted beets, arugula, walnuts, balsamic vinegar, 1 tablespoon olive oil, 1/4 teaspoon salt, and 1/8 teaspoon pepper together in a bowl until well combined.